SD-JWT

JWT for Selective Disclosure. https://www.ietf.org/archive/id/draft-fett-oauth-selective-disclosure-jwt-02.html
Flow:
- Issuer passes two objects to the holder:
  - SD-JWT (signed JWT, contains CLAIMs, HASHES OF VALUES, and a signature)
  - SD-JWT-SVC (Salt Value Container, contains CLAIMs, SALTS, and JSON-Encoded VALUES)
- Holder
  - creates SD-JWT-R (unsigned subset of the SD-JWT-SVC) i.e. holder can see the values of the claims that are released.
  - passes SD-JWT and SD-JWT-R to the verifier
- Verifier
  - Uses salts to verify hashes
  - Can then trust the SD-JWT
Extensions allow for "holder binding" to eliminate replay attacks.
Pros:
- User sees values that are passed on
- User is in charge of the selection of claims
Cons:
- Breaks existing JWT flows

JSON-LD

JSON for Linked Data https://json-ld.org/
Extension of JSON with "@-Claims" that point to external resources
Most prominent: "@context" which links to a schema that describes the JSON at hand
Why is this relevant?: (I think) it provides a way to pass around arbitrary JSONs from Issuer via Holder to Verifier.
- The wallet software does not need to understand the JSON a-priori (e.g. at development time)

European Learning Model https://htmlpreview.github.io/?https://github.com/european-commission-empl/European-Learning-Model/blob/master/rdf/ap/edc/documentation/EDC-generic-no-cv.html#evidence
Extensive (~~extremely overly complicated~~) model to define all kinds of learning: over 480 properties to capture and validate all types of learning
Based on
- JSON-LD
- Verifiable Credentials: https://www.w3.org/2018/credentials/

https://www.imsglobal.org/sites/default/files/Badges/OBv2p0Final
json-ld specification: https://openbadgespec.org/v2/context.json
Less complex than ELM
Focussed on learning, attesting an achievement
Signed (is it a JWT?)
Typical quote:
- "The Assertion issuer is authorized to award Assertions of the declared BadgeClass (typically by being the issuer of the BadgeClass.)"
- "Additional checks may ensure that: The issuer Profile awarding the Assertion is trusted to have declared accurate information about its identity (typically via Endorsement)."
- => freely translated by Marcus: "We do not have a trust model yet"

Nice read: https://medium.com/@leifj/trust-does-not-scale-94bab5b67f5c
eduGAIN
EBSI
OID-Fed
ToIP Whitepaper
- Intermediaries (as in Federated Identities) are bad: "Trust Gap" from scaling up
- Intermediaries (as in DI) are good
- Describes the trust between Issuer and Verifier
  - Pretty much a "cloudy" kind of thing => This is where (IMO) eduGAIN and OID-Fed have strongest points
New concept: Holder Binding